This invention relates generally to the field of internal combustion engines, and more particularly to an improved cam engine of a type in which the usual crank shaft is eliminated, and the pistons, and associated connecting rods transmit motion to a rotating cam element having an axis of rotation parallel to the line of action of the pistons. Reference is made to my prior U.S. Pat. No. 3,805,749 which discloses a cam engine of this general type, the present disclosure relating to an improved form of that engine.
While inherently functional in its original form, I have found that certain structural elements thereof are capable of substantial improvement.
One problem has been that of maintaining the operational temperature of the disk intake-exhaust valve within reasonable limits. Unlike poppet type valves, the disk valve of the engine disclosed in my prior patent is not located in a cooling medium, and is not easily cooled by water jacketing. Since the clearance between the valve and its housing must be maintained within relatively small limits to preserve compression, overheating can cause sufficient expansion to result in seizing of the valve against its housing.
Another problem which I have encountered is that of igniting the fuel mixture in those cylinders which do not have a spark plug. In my earlier construction, the ignition was accomplished by a passage connecting opposed cylinders which fired simultaneously and extended through the disk valve. This has caused a heating effect on the disk valve, and its clearance with the housing.
At high speeds, it becomes desirable to provide more rapid opening and closing of the intake and exhaust valve cycles within the same degree of rotation of the drive shaft. This cannot be accomplished by altering cam lobes as in a conventional poppet valve engine, but the desired result is necessary for efficiency at such high speeds.
Since there is no pivotal interconnection between the connecting rod and piston in each of the individual cylinders, owing to the lack of a crankshaft, it is desirable to provide means whereby an individual piston has a degree of ability to correct for misalignment relative to the connecting rods, and thereby avoid unnecessary pressure on the adjacent cylinder walls.
Finally, it is desirable to reduce friction at the points of communication between the cams on the cam plate connected to the lower end of the connecting rods and the corresponding cam lobe on the cam element which drives the motion output shaft.